Variable-lead valve-gear for locomotives.



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Ptented Dec. 6', 1910.

W. L DAVIS. VARIABLE EEAD VALVE GEAR FOP. LOCOMOTIVES. APPLICATION FILED TEIL-12, 19.10.

W. L. DAVISE` VRABLB LEAD VALVE GEAR FOR LOGOMOTIVBS. APPLIGATION FILED FEB. 12, 1910.

.Patented Dea 6119MB.

2 SHEETS-SHEET 2.

fermes.

''To-cZZ whom 'it mag/concern: I*

Beit 'known .that I, WILLIAM LYNN UNITED STATES rA'rnN'r ernten.

.WILLIAM LYNN DAvIs, or ToPEKA, KANsAs.

D'AvIs,'.a citizen of the United States, and

resident of Topeka, 4Kansas, have invented -certain new' and useful Improvements; in

Variable-Lead Valve-Gear for Locomotwe- `4 Engines, o f which the following is a full,

true, clear, and vexact description, such 'as f will enable othersI skilled in the art to makev l anduse the same.

MyV invention relates to improvements inv -valve gea-rs, and has part1cular vreference `to improvements in Walscheart type locomotive valve gears'.

The object of my invention is to so im- -fprove the. construction and operation of Walsclieart type locomotive valvegearsthat the lead of the valve will be, automatically viewof the principal parts of a locomotive.

altered'in inverse proportion jto 'the varia- -tion'of the cut-off by the adjustment'of the reversing lever; and will operate. in suchv manner during both'forward and reverse;

movements of the reversing lever.

- My invention'consists in a locomotive valve gear having the functions and embodying the features of construction typically indi; cated and disclosed in the accompanying drawings and detailed description,

' The invention will bev readily understood 'byrreferenc'e to said drawings, in which:

Figure 1 is a diagrammatic perspective engine, provided with an improved Wal- 'scheart valve gear embodying my invention;

Figs. 2 and 3 are detail fragmentary hori- Zontal sections on the lines 2-2 andv 3 3 respectively of Fig. 1; Fig. 4l is a detailed `fragmentary verticalsection on the line 4 4 of Fig. 3,1and Figs. 5 to 9 inclusive are line diagrams of the valve motion or gear in different operating conditions, the moving membersl being illustrated by their center lines' only, and the connections between movis illustrated.

ing parts being indicated by arcs of circles. ,A locomotiveengine of well-,known type The parts which are fixed upon the frame of the locomotive are: the engine cylinder, 1,' the cross head guides, 5,

{theframe part, 16, the link. brackets,17,

the standard, 3G, and thebearings `(not shown) for the several rocking shafts, 26,

22 and 28. JThe piston2within the cylinder isconnected to thecrossheadig 'by the A 'f' ypiston rod, 4,' and-the 'cross headvisfljoined Slzaecication of Letters Patent.

by the usual connecting rod, 6, to thecrank, 7, of the driver, or driving wheel, 8. VThe ports, 9, of the cylinder are controlled by a valve suchasthe slidingvalve, 10, which 1s actuated by thevalve motion about to be described( -The valve derives its motion from the return crank, 20, fixed on the crank pin, 7, of the driver, and from the cross head,

31 represents the valve rod.

28 is a rocking shaft adjacent to the rear end of. the valve rod, and having two rocking arms, 29 and .30, the latter being connected to the rear end ofthe valve rod.

head is ,establishedv through the crosshead hanger, 11b, the link, 11a and the'lap-andlead lever, 11,- the latter having its upper end pivoted by a pin llc'to the rocking arm, 29, which, as stated, joins the valve through the mediumof rocking ,'shaft, 2 8, arm, 30, and valve rod, 31.

4The connection between the valve and the the crank pin, 20a, on the return crank 20, the rod, 21, the oscillating, curved link, 15, pivotally fixed on'the frame of the engine, the radius rod, 12, the fulcrum pin, 13, and fulcrum block, 321,y from which latter the remainder Aof the connection is Itraced through the upper end of the lap-and-lead lever and the parts, 29,128, 3() and31. The reciprocating motionof the cross head and the rotary motion of the return crank combine to produce a single lesser' movement of the upper end of the combination lever, hence of'the valve. The movement of the lower end of the combination lever, 11, is determined by the stroke of the piston and cross head. 'The movementof the radius rod, 12, is determined by the position which the block, 14,.may, at the moment, occupy in the curved link, 15, said link having a definite oscillation impartedto it by the re turn crank on'the driver.' Assuming now that the fulcrum pin, 13, is fixed at definite point on the combination lever, the move- 'ment imparted to the valve will comprise the sum of the swinging movement of the upperend or arm of 4the combination lever plus the horiZontalthrow imparted by the link, 15, and radius rod, If the link block, 14, is alined with 'the trunnions 'of the definite position on the frame andhaving a i Patented Dec, 6, 1910. Application led February 12, 1910. Serial No. 543,620.

The connection of the v alve to the cross I -return crank on the `drive wheel comprises links,f15, the only motion upon the valve will be the .minor swinging movement of the upper arm of the combination lever, foratsuch time the radius rod will be staradius rod and the reversing lever, 25, comprises the link, 24, the rocker arm, 23, the fixed rocking shaft, 22, the rocker arm, 27, the rod, 27, the rocker arm, 26a, the fixed rocking shaft, 2G, the arm, 25, and the'reach rod, 25a.

In the diagrammatic figures the rod, 2T,

is' represented as though connected ,directly to the reversing lever, 25. The proportion of the parts are such that when the reversing lever is in vertical position the link block will be held at the center of thevlink. vMovement ofthe reversing leveri'in either direction from the" vertical will shift the 'block' toward? one end of the link, and the latter being in constant oscillation will impart to the radius rod a movement proportional to the distance of the link block froml the center of the link. A reversal of the reversing lever from one side of the vertical position to the other causes the block to be shiftedto the opposite end of the link yand, reverses the reciprocat-ion'of the valve with respect to the piston, causing a reversal in the movement of the engine.

In thus far describing the operation of the valve motion I have referred to the fulcrum orv motion juncture pin, 13, as occupying a ixed position on the combination lever, but this is not the case.. Instead, the'combination lever is provided with' a vertical slot, 32, extending downwardly from a point adjacentto the upper pivot, and containing the fulcrum block, 32, in which the pin, 13, is placed. A bell crank, 35, is mounted on the upper end of the standard, 36, and its lower arm, 37, is connected to the fulcrum pin, 13, (and radius rod) by a curved lifting link, 372 the lower end of which is in the form of la yoke fastened to the ends ofthe fulcrum pin, 13. It will now be obvious that by moving the bellcrank, 35, the fulcrum pin, 13, and the forward end of the* radius rod may be rais-ed and lowered on theV combination lever, "such movement varies the distance between the centers of the lever pivots, 13, and 11C. In other words, such movement variesthe relativelengths of the upper. and lower arms of the combination lever and alters the degree `of swinging mechanism between the sha-ft', 22,

movement of the armiof the combination lever. B y lowering the fulcrum pin, 13,

-the throw ormovemen't of the valve .is in creased, and by raising the 'fulcrum pin'the movement of the valve may be diminished.

valve in this manner when the motion of the radius is reduced: by the approach of the link block to the center of the link, and rev-ersely it is desirable to subtract from the 4motion of the 'valve in proportion to the movement of the link block, toward either end of the link, in order that the lead ,shall be increased as the-cut-ofl' is decreased and vice versa. As' a means of lifting or `adjusting the juncture fulcrum of the combination lever and radius rod I employa-rocker arm, 40, on the shaft, 22, and a link,l 39, which extends from the end-offsaid arm to the up-j` right arm, 38, of the bell crank, 35. -It will now be understood that the link block, 14, at one end ofthe radius-rod and-the motion juncture fulcrum, 13 at the other ,end of the radiusrody receive vertical adjustment kfrom -the same source, namely, the.,.r'ocker shaft, 22; in other words, the reversing lever which said shaft represents, because connected thereto. Opposite movements of the rock shaft and arm,- 23, produce reversalsof the valve, but both movements ofthe r ck shaft produce the same effect upontlie no- It is desirable to add to the stroke of the j tion juncture fulcru-m, 1-3. This is'brought about by so placing the arm, 40., on theshaft,

22, that'itwill make a straight line with ,the link, 39,'when the reversinglevertandirock shaft are in 'neutral positions. L, i'

Inpratice I .constlructi-,- l the motion junctureapin is `close to the lower end of theslot, 32, inthe combinationalever at times when'. themlink. block. ,is in central position. A movement of thelink block 'in eitherdirection from its central position in he partei-soi that the link being occasioned -by the rocking of f causes the j, elevation of the fulcruin, 1'3, and consequent reduction'ofvalve lead., yThis being brought`| about by the swinging of the toggle, comprising the arm,

10,and link, 39.

- Idesire thatit understood that the valve motion herein shown is merely typical of my invention andv that",l with types'of lValscheart `valve geared engines fflit is'- desirable and necessary to considerablyjnodify the structure herein shown. .Fort etample, where it is necessary to place the lfulcrum it will be necessary to reversel the action and position olf-the bell crank lever, 35, so that as thereverse lever, 25, is moved from this central position to increase the cut-off the fulcrum, 13, willwbe lowered instead of raised, as in the' present instance. These and other modifications may be made .withoutdeparting from the spirit of my invention.I

.juncturepin,.l3, above the connection of the ap-and-lead lever,11, to the valve stern, 3l,

erases Having' thus described my invention, I

.claim as new and desire to secure by Letters Patent 1. Thel herein described improvement in `With the engine cross-head for actuation thereby and having its other end operatively connected to the valvev rod, a ulcrum block shiftablej longitudinally upon said lever. a

radius rod extending from said'link blockl to said fulcrum block for communicating the Inc-tion of said link to said combination lever, a reversing lever and a system" of levers connecting the same with both said blocks andadapted to move said fulcrum block toward the valve rod Vconnection oi:

the combination lever` When the link block is moved from its central position toward either end of said link, and vice versa.

2. The herein described limprovement kin valve gears for locomotive engines comprising an oscillating link pivotally mounted or trunnioned upon `the engine frame iu combination With means for oscillating said link from the driving Wheel of the locomotive, a link block in, and shittable from end to end of; said link, a combination lap-andlead lever having one end connected with the engine cross head for swinging reciprocati'on thereby and having its other end operatively connected with the valve'rod of the' engine, 'a fulcrum shitable longitudinally upon said lever, a radius rod extending from said link block to said ulcrum andv vvalve lap as thel valve cut-oil' is increased,

and vice versa. y

3. The herein described improvement in Vvalvegears for locomotive engines comprising an oscillating link pivoted or trunnioned on the frame of the engine, a means ifor oscillating said link by the rotation of j the driving Wheel of the locomotive, in combination -With a link lblock shittable in said link, 'a reversing lever for shifting said block in said link, a combination lap-and- `lead lever having'one end 'connected Withandac't-uatedby the engine cross head and Vhavingyits other end operatively connected with the valve rod of the engine, a lradius rod connecting said link block to said com-` bination lever lat a point adjacent .to thev valve rod connection of the latter 4and mechanism connected with and actuated by .said

reverse lever for shifting the connection of said radius rod and combination lever in inversed conformity to the movement imparted to said link block by said reverse lever.

4. The herein described improvement in valve gears for locomotive engines comprising an oscillating link trunnioned upon the frame of the engine and means for oscillating said link from the driving Wheel of the locomotive, in combination With a link block in, and shiftable from end to end of, said link, a combination lap-and-lead lever having one end connected to and actuated by the engine cross 4head and having its other end operatively connected with the valve rod of the engine, a radius ro-d extending from said link block to a pivotal point on said combination lever adJacent to the valve rod connection of the latter, a reversing lever and a system of levers connecting the same with both ends of said radius rod and operable to shift the link block in said link and, proportionally to the movement of said block ayvay from its central position in the link, diminish the distance between said valve rod connection and said pivotal point of theradius rod and combination lever. V

' 5. The herein' described improvement in valve gears for locomotive engines comprising an oscillating link trunnioned on the engine frame -in combination with means for oscillating said link from the driving Wheel of the locomotive, a link block shiftable in said link, a combination lap-and-leadlever having A.one end connected With the engine cross head and having its other end operatively coi'inected with the valve rod, and a fulcrum block longitudinally. shiftable on said lever, a radius rod connecting said link block and said fulcrurnV block, a reversing lever coupled to said link block and adapted to shift said link block from end to end of said link, abell crank coupled to said fulcrum block and adapted to move said fulcrum blocktoWard and from the valverod pling lever being constructed to form.l a

straight line when the reversing lever .is in its neutral position.

' In testimony whereof, I have hereunto set 'y my hand, this 7th day of February, 1910, in

the presence of two subscribing witnesses. ILLIAM LYNN DAVIS.` Witnesses I JOHN Hi LINN, LULU KELLY.v 

